I understand that it is not illegal to purchase/buy. The seller is the person breaking the law, no?

So, if there is a transaction between you and me, you the seller, me the purchaser, you the seller is breaking the law, not me the purchaser.

And that is where they get you with a conspiracy charge. The seller cannot commit his crime of selling the magazine without a willing buyer. Thus the willing buyer is an actual participant in the conspiracy to commit the crime.

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